Assembly device for assembling dismountable or modular elements

ABSTRACT

The invention relates to an assembly device for elements of the type comprising a framework and at least one spacer or panel extending transversely to said framework. In accordance with the invention, the device comprises two assembly bodies (100, 200) insertable in respective hollow bars constituting a portion of the framework, each assembly body having a central locking portion (101, 201) capable of penetrating into a hole in a panel to be supported, together with a peripheral portion (102, 202) capable of bearing against one of the faces of said panel; the central locking portions (101, 201) constitute a sloping ramp bayonet coupling, thereby enabling said bodies to be deformed radially outwards by relative rotation between the two assembly bodies, thus locking them automatically in the associated hollow bars. The invention is applicable, in particular, to pieces of furniture for provision in kit form, and for various types of element and/or hollow bar.

The invention relates to assembling dismountable or modular elements, inparticular furniture elements in order to assemble furniture in kitform.

More precisely, the invention relates to an assembly device forassembling dismountable or modular elements, said elements being of thetype comprising a framework and at least one spacer held by saidframework and disposed substantially transversely relative thereto.

Numerous systems already exist for assembling a framework and spacers orpanels in order to provide various dismountable or modular pieces offurniture.

Firstly there are systems using a sleeve and a screw at the end of tworisers disposed on either side of a panel: one of the risers has ashoulder for supporting vertical forces and the panel is sandwichedbetween the two risers, with assembly being assembled merely by rotatingone of said risers several times relative to the other, thereby screwingthem together.

More generally, there are systems based on the principle of connectionmembers glued or welded to the ends of risers or partitions. Thesesystems go from very simple techniques using screws whose heads arereceived in the panel being screwed (round-headed wood screws) to morecomplex systems using an excentric type of locking catch (the catch isrotatable about an axis parallel to the axis of the partition and isrotatable by means of a tool so that its edge is received in a grooveprovided for this purpose in a connection member applied to the end ofthe riser).

Mention may also be made of systems having threaded endpieces applied tothe ends of risers constituting portions of the vertical framework, suchas the system described in French utility certificate number 2 557 783.

However, these various techniques suffer from several drawbacks.

In general, they are limited to round section frameworks since therelative positioning of successive risers (about their axes) isdifficult to control (relative rotation when screwing items together isalways subject to an angular positioning error once the items have beenassembled and this is unfavorable with respect to the appearance of thefinished piece of furniture).

In addition, assembly usually requires a special tool to be used, exceptfor tubes having endpieces and screws applied thereto which are screwedtogether through a slab of wood (however this technique is expensive andnot very reliable).

Mention may also be made of U.S. Pat. No. 3,338,605 which describes asupport structure suitable for making storage items, tables, orseparating partitions.

The structure described in this American patent is essentiallyconstituted by a connection formed by three mutually lockable elements,which connection can be clamped to the rim of a wall inserted in alateral notch in the connection. Clamping is obtained by co-operationbetween a ramp and a ridge provided on two of the three elements: it isthen necessary to provide fluting and slots in order to provide twolocks against rotation, in order to lock all three elements together.

Such a structure does not require a special tool, but it is complex andremains limited to end-to-end assembly with snap-fastening connections.

The state of the art is illustrated in general by British patent number1 402 925, U.S. Pat. Nos. 3,869,218, 3,661,411, and 3,890,022, and byGerman utility model 84/30 322.

The various systems that have been developed for assembling panels andpartitions together are not well adapted to assembling together the barsof a framework. In any event, these systems do not set out to ensurethat the bars remain perfectly in alignment, which is neverthelessessential if the pieces of furniture are to support heavy loads.

Doubtless this explains why manufactures are not keen to split up avertical load-carrying riser into a plurality of subassemblies, sincethey are well aware of the risks of damage that can arise from applyingheavy loads to such pieces of furniture, particularly since such loadsare generally not uniformly distributed. A particular consequence ofthis is that prepacked kits enabling purchasers to assemble pieces offurniture are themselves always at least as long as the one-piece risersare high (e.g. 1650 mm for office furniture which is 1650 mm high, or1700 mm for a chest of drawers assembly which is 1700 mm high).Nevertheless, it is well known in this field that the size of packagesconstitutes a very important parameter.

The object of the invention is to provide an assembly device whichavoids the drawbacks mentioned above while still being simple in designand reasonably cheap to produce.

Another object of the invention is to provide an assembly device whichmakes assembly quick and easy, and in particular which does not requireany tool for assembling the items concerned or for taking them apart.

Another object of the invention is to provide an assembly device whichis compatible with a very wide range of bar profiles without therebycomplicating assembly while nevertheless ensuring that the bars areaccurately aligned, both with respect to vertical alignment (which isessential for carrying forces safely) and for angular positioning (whichis important for the appearance of the assembled piece of furniture).

Finally, an object of the invention is to provide an assembly devicewhich remains completely hidden once assembly has been completed,thereby leaving the final appearance of the assembled piece of furnitureunaffected.

More particularly, the present invention provides an assembly device forassembling dismountable or modular elements, said elements being of thetype comprising a framework and at least one spacer held by saidframework and disposed substantially transversely relative thereto, theassembly device being characterized by the fact that it comprisesfirstly a first assembly body insertable in a hollow bar constituting aportion of the framework, said first assembly body comprising a centrallocking portion capable of penetrating through a hole associated withthe spacer, and a peripheral portion connected to said central portionand having a free edge capable of bearing against a face of said spacerin a zone surrounding the hole provided therethrough, and secondly asecond assembly body capable of bearing against the opposite face of thespacer, said second assembly body having a central locking portioncorresponding to the central locking portion of the first assembly bodyand likewise capable of penetrating into said hole in order toconstitute a sloping ramp bayonet coupling, the peripheral portion ofthe first assembly body being, in addition, radially outwardlydeformable under the effect of traction exerted on the central portionof said first assembly body, such that relative rotation of the twoassembly bodies in order to couple them together provides such tractionand thus automatically locks the first assembly body in the associatedhollow bar.

It is advantageous to provide for the peripheral portion of the firstassembly body to include parallel facets corresponding to at least someof the inside faces of the associated hollow bar, said facets beingconnected via a common central face to the central locking portion ofsaid body; this applies, for example, when the cross-sections arepolygonal, and in particular when they are square or rectangular.

It is advantageous for the first assembly body to have slitsfacilitating radial deformation thereof under the effect of tractionexerted on the central locking portion of said body. In particular, theslits may be provided in the edges of the peripheral portion of theassembly body, and they may extend into the common central face of saidbody; more precisely, the slits may be organized in diagonal planesparallel to a common direction which corresponds to the central axis ofthe associated hollow bar.

In accordance with a particularly advantageous characteristic of theinvention, the central locking portion of the first assembly body issubstantially in the form of a cylindrical chimney terminating in a maleor female sloping ramp bayonet coupling.

In a first case, the male coupling includes a projecting transversehead, said transverse head including at least one sloping bottom facettecapable of co-operating with a sloping ramp provided on thecorresponding central locking portion.

In a second case, the female coupling includes at least one inclinedramp disposed inside the chimney, said ramp being suitable forco-operating with the projecting transverse head provided on thecorresponding central locking portion. Preferably, the sloping ramp isdelimited by two snap-fastening ridges; in particular, the sloping rampmay be essentially plane and may extend perpendicularly to an inletfacette delimiting an orifice provided to receive the projectingtransverse head of the corresponding central portion. In a variant whichis preferred for reasons of reliability, the female coupling includestwo sloping ramps symmetrically disposed about the axis of the chimney.

In accordance with a particularly advantageous characteristic, thesloping ramp bayonet coupling takes effect after the two assembly bodieshave rotated through approximately one quarter of a turn relative toeach other: it is then easy to see how such a system is quick and easyto implement compared with systems based on screws requiring the barsconcerned to be rotated relative to one another through severalrotations.

Preferably, the male and female sloping ramp bayonet couplings furtherinclude quick snap-fastening means enabling them to be temporarilylocked together by axial displacement of the two assembly bodies priorto said bodies being rotated relative to each other; in particular, thequick snap-fastening means is constituted by a stud and dimple system,preferably having two studs on the projecting transverse head of themale coupling, and two dimples on the inside wall of the chimneycarrying the female coupling.

In a particularly advantageous embodiment, the first and second assemblybodies are generally identical in structure, and differ from each otheressentially only by the sloping ramp bayonet coupling; in particular,the two assembly bodies include respective peripheral portions such thatidentical hollow bars can be used on either side of the spacer inquestion, for example the peripheral portions of the assembly bodies aresubstantially square or rectangular in cross-section. In a variant, whenthe assembly device is associated with a section bar having angularinternal voids, the peripheral portions of the assembly bodies beingcomplementary in cross-section, having corresponding angularprojections.

In another advantageous embodiment, the second assembly body is in theform of a cylindrical plug whose main portion constitutes the centrallocking portion terminated with male or female sloping ramp bayonetcouplings, and whose remaining portion is essentially undeformable andconstitutes both an abutment surface and a mask for hiding the bayonetcoupling. This applies, for example, for the top end of a verticalframework whose appearance is to be preserved without being detrimentalto the reliability of the assembly.

Finally, it is advantageous for each of the assembly bodies to beconstituted by a single piece of plastic material, preferably obtainedby injection molding: this gives rise to a highly satisfactoryproduction cost even for complicated shapes (as applies to theabove-mentioned variants having angular projections).

Other characteristics and advantages of the invention appear moreclearly in the light of the following description relating to aparticular embodiment and made with reference to the accompanyingdrawings, in which:

FIG. 1 is a perspective view showing two assembly bodies constituting anassembly device of the invention, with cut-away portions showing thestructure thereof more clearly, in particular for the female bayonetcoupling having a sloping ramp;

FIG. 2A is an axial section through the two bodies of FIG. 1 (theassembly body having a male bayonet coupling is, however, in this caseshown above the body having the female coupling);

FIG. 2B is a similar axial section on a plane orthogonal to thepreceding section;

FIG. 3 is a plan view of the same bodies (with FIGS. 2A and 2B beingsections on A--A and B--B of FIG. 3);

FIG. 4 is an axial section through the device of the invention inassociation with two hollow bars on each side of the panel to besupported (the device is shown in its final position in this case, withan effective bayonet coupling linking together the two assembly bodies);

FIG. 5 is an exploded view showing an example of vertical organizationof the component parts of a piece of furniture having casters and twohorizontal slabs (one of the assembly bodies can be seen at the top inthe form of a plug, whereas both bodies are substantially identical forthe bottom panel which has two hollow square section bars bearingthereagainst);

FIG. 6 is a cross-section through another hollow section bar (which barhas angular internal voids and external T-slots for the rabbet of awall, or for a positioning catch, or for a decorative strip insert), inwhich a complementary assembly body having angular projections isinserted, thereby encouraging the spread of clamping forces and alsoavoiding compressing the bottoms of the grooves; and

FIGS. 7A and 7B show two examples of pieces of furniture that can easilybe assembled using the device of the invention, with the device beingused on all of the horizontal slabs.

DESCRIPTION OF PREFERRED EMBODIMENTS

The assembling devices described below makes it possible to assemble anddismount a very wide variety of dismountable or modular elementsquickly. The elements in these examples to constitute furniture having aframework and at least one spacer held by said framework substantiallytransversely thereto. In the furniture, the spacer is generally in theform of a panel or a shelf. However, other applications such as standsor display units, for example, naturally may be envisaged in which thespacers are mere thrust washers.

Each assembly device of the invention is essentially constituted byfirst and second assembly bodies. The first assembly body is insertableinto a hollow section bar that constitutes a portion of the frameworkand associated with the second assembly body so as to define a bayonetcoupling having a sloping ramp. At least the first assembly body is suchthat relative rotation between the two assembly bodies for the purposeof the bayonet coupling also automatically locks the first assembly bodyin the associated hollow section bar. In the embodiment described indetail with reference to FIGS. 1 to 4, the first and second assemblybodies are almost identical in structure, and differ from each othersolely by their male or female sloping ramp bayonet couplings.Naturally, other possible variants also exist, such as a variant inwhich the second assembly body is a cylindrical plug with a male orfemale sloping ramp bayonet coupling, as described below with referenceto FIG. 5.

The assembly device 1 shown in FIGS. 1 to 3 comprises a first assemblybody 100 and a generally corresponding second assembly body 200. As canbe seen, the assembly bodies 100 and 200 differ from each other solelyby their central locking portions 101, 102 that have respective male andfemale bayonet and sloping ramp couplings at first ends thereof. As aresult, portions of the second assembly body 200 which correspond toportions of the first assembly body 100 are given the same referencenumerals plus one hundred.

The first assembly body 100 has, in addition to its central lockingportion 101, a peripheral portion 102. The peripheral portion 102 isconstituted by facets 104 that are disposed at least generallycorrespondingly to at least portions of internal faces of the associatedhollow section bar and parallel to a coupling axis of the centrallocking portion that extends from the first end thereof to an opposite,second end. These facets are connected to the second end of the centrallocking portion 101 by a common central face 105 and terminate at oneedge (the bottom in FIG. 1) in a common free edge 103 that is spacedfrom the common central face in the direction (downward in FIG. 1) fromthe second to the first end of the central locking portion.

The central locking portion 101 is suitable for penetrating into a holethrough a spacer panel (600 in FIG. 4) to be held, while the free edge103 is suitable for bearing against a face of said panel surrounding thehole. As a result and in accordance with an essential characteristic ofthe invention, the peripheral portion 102 of the first assembly body 100is radially outwardly deformable by axial traction on the centrallocking portion 101 in the direction the free edge is spaced from thecentral face. Thus, if the assembly body 100 is inserted in anassociated hollow section bar of corresponding cross-section so that thefacets 104 come adjacent to the inside faces of the hollow section bar,then when traction is exerted on the central locking portion 101 in inthe direction from the central face 105 to the free edge 103 on the faceof the panel, the traction deforms the central face, and thus, radiallyoutwards, the facets 104 of the peripheral portion 102. This radiallyoutwards deformation or expansion has the effect of pressing each of theparallel facets 104 firmly against the corresponding inside faces of thehollow section bar, thereby ensuring reliable locking without assistancefrom any tool.

It is advantageous for this to provide the first assembly body 100 withslits 106 between the facets 104 and extending into the common centralface 105. Such a configuration is further advantageous in that as itleaves a continuous bottom strip adjacent to the free edge 103 of theperipheral portion 102, thereby maintaining mechanical integrity of theassembly during radial deformation of the peripheral portion. It willalso be observed that the slits 106 are disposed in diagonal planesextending parallel to a common direction which corresponds to thecentral axis of the associated hollow section bar. Naturally a degree ofsymmetry is advantageous insofar as the radial deformation of theperipheral portion of the assembly body then occurs in the same way foreach of the side facets of said body. The isotropic nature of suchdeformation helps to center the hollow section bar relative to the axisof the central locking portion 101, and thus to align two adjacent barson either side of a panel held between them.

The central locking portion 101 of the first assembly body 100 is, inthis case, substantially in the form of a cylindrical chimneyterminating in a sloping ramp bayonet coupling (female in this case).The cylindrical chimney connects directly to the common central face 105via a connection constituting the fastening point enabling theperipheral portion of the body to be deformed radially outwards underthe effect of traction exerted on the central portion 101. The cut-awayat the end of the cylindrical chimney shows the exact structure of thesloping ramp bayonet coupling (with the portion taken away beingidentical to the portion that is visible, the cylindrical chimney havingaxial symmetry about its axis). The female coupling given a generalreference 107 includes at least one sloping ramp 108 disposed inside thechimney 101, said ramp being intended to co-operate with a projectinghead provided on the corresponding central locking portion of the otherassembly body. The sloping ramp 108 is essentially plane in this case,extending perpendicularly to an inlet facette 108 delimiting an orifice110 provided for receiving the projecting head of the correspondingcentral portion. Two snap-fastening ridges 111 and 112 can also be seen,and their function is described below. In practice, two sloping ramps108 are preferably provided, disposed with axial symmetry about the axisof the cylindrical chimney.

The structure of the second assembly body 200 is now described, and inparticular the structure of the male coupling which, in association withthe above-described female coupling, serves to define a sloping rampbayonet coupling.

The assembly body 200 comprises, like the first assembly body 100, acentral locking portion 201, and a peripheral portion 202 connected tosaid central portion and having a free edge 203. The peripheral portion202 includes parallel facets 204 which are connected via a commoncentral face 205 to the central locking portion of said body. Slits 206can also be seen for facilitating radial deformation of the assemblybody 200 under the effect of traction exerted on the central lockingportion 201 thereof. As before, the slits 206 are provided in the edgesof the peripheral portion 202 of the assembly body and they extend intothe common central face 205 thereof, with said slits being organized ontwo diagonal planes parallel to a common direction which corresponds tothe central axis of the hollow section bar associated with the assemblybody. The central locking portion 201 is similarly in the form of achimney which is hollow like the central portion of the other assemblybody, however this chimney is terminated by a male coupling 207. Thus,going from the central portion 250 of the cylindrical chimney 202 therecan be seen a coaxial cylindrical appendix 251 projecting beyond theplane of the free edge 203. The appendix 251 carries a projectingtransverse head 252 whose general cross-section (in a planeperpendicular to the axis of the chimney) corresponding substantially tothe cross-section of the inlet orifice 110 provided in the correspondingcentral portion 101 of the assembly body 100. The top edge of theprojecting transverse head 252 is preferably rounded, running smoothlyinto two side faces 252, which faces come into contact with the inletfacets 209 delimiting the above-mentioned orifice 110. It is alsoadvantageous to provide for the transverse head 252 to include at leastone sloping bottom facette 253 suitable for co-operating with thesloping ramp 108 provided in the corresponding central locking portion101. In order to engage both sloping ramps 108 provided in the assemblybody 100, two sloping bottom facets 253 are naturally provided and aredisposed with axial symmetry about the axis of the chimney 201.Naturally, the slope of these facets 253 corresponds to the slope of theassociated sloping ramps 108.

The sloping ramp bayonet coupling 107, 207 operate as follows. Once theprojecting transverse head 252 has penetrated far enough through theorifice 110, relative rotation between the assembly bodies 100 and 200causes each sloping bottom facette 253 to engage the firstsnap-fastening ridge 111. By continuing rotation, the facets 253 go pastthe ridge 111 and then engage the associated sloping ramp 108, with thesecond ridge 112 then constituting an abutment preventing any furtherrelative rotation between the two bodies. It can thus be seen that thesloping ramp bayonet coupling of the invention takes effect after thetwo assembly bodies 100 and 200 have rotated relative to each otherthrough about one fourth of a turn. This shows how the system of theinvention is quick and easy compared with prior systems requiringsection bars having end inserts for screw connection to be rotatedthrough several full revolutions.

It is also advantageous to provide for the male and female sloping rampbayonet couplings 207 and 107 to be provided with quick snap-fasteningmeans enabling temporary locking to be obtained by axial snap-fasteningof the two assembly bodies 100 and 200 prior to rotating said bodiesrelative to each other. One possible example of such rapidsnap-fastening means is illustrated using a system of studs and dimples.Thus, there are two studs 255 on the projecting transverse head 252 ofthe male coupling 207 and two corresponding dimples 113 on the insidewall of the chimney 101 carrying the female coupling 107. In FIG. 1, theposition of the dimple 113 is deliberately offset in order to make itvisible, and in fact it is situated in the cut-away portion of thechimney 101. Thus, merely moving the two assembly bodies 100 and 200towards each other so that the projecting transverse head 252 isinserted into the orifice 110 suffices to obtain temporaryinterconnection by axial snap-fastening between the two bodies.Naturally, the dimensions of the component parts of the assembly bodiesare selected in such a manner that each of these bodies is in contactwith one of the faces of the panel to be held when said bodies aretemporarily fastened together by the axial snap-fastening, such thatrelative rotation of the bodies has little clearance to take up and isessentially concerned with providing the radial outwards deformation ofthe peripheral portions of the bodies.

As can be seen in FIG. 3, the sections of FIGS. 2A and 2B improveunderstanding of the exact structure of the assembly bodies 100 and 200.It can be seen that each of the assembly bodies 100 and 200 isconstituted in this case by a single piece which is preferably made byinjection molding plastic material. The sections of FIGS. 2A and 2B showthat the common central faces 105 and 205 of the assembly bodies 100 and200 are at an angle α relative to a plane perpendicular to the commonaxis 500 of the assembly bodies. The person skilled in the art willreadily understand that such an angle α is advantageous for obtainingoptimum sideways and outwards deformation of the peripheral portions ofthe assembly bodies. For assembly bodies having a thickness of about onemillimeter, the angle α is preferably selected to be close to 30°. Thesefigures thus clearly show the structure of the component parts of eachof the assembly bodies, which component parts are recalled below. Theassembly body 100 has a central locking portion 101, a peripheralportion 102 connected to said central portion and having a free edge103, parallel facets 104 connected via a common central face 105 to thecentral locking portion 101, and slits 106 facilitating radialdeformation of the body under the effect of traction exerted on thecentral locking portion 101 of said body. There is also a female slopingramp bayonet coupling 107 having two sloping ramps 108 extendingperpendicularly to an inlet facette 109 delimiting an orifice 110, witheach sloping ramp 108 being delimited by two snap-fastening ridges 111and 112. Finally, the assembly body 100 has two dimples 113 for fastsnap-fastening in an axial direction between the two assembly bodies 100and 200. Similarly, the assembly body 200 has a central locking portion201, a peripheral portion 202 connected to said central portion andhaving a free edge 203, parallel facets 204 connected via a commoncentral face 205 to the central locking portion 201 of the assemblybody, and slits 206 facilitating radial deformation of said body. Therecan also be seen a male sloping ramp bayonet coupling 207 having aprojecting transverse head 252 having two sloping bottom facets 253 andtwo studs 255 for rapid snap-fastening after axial displacement.

The axial section of FIG. 4 shows how the device of the invention isused for assembling two hollow section bars on either side of a panel tobe supported.

There can thus be seen a panel 600 having a hole 601 through which thecentral locking portions of the two assembly bodies in question canpenetrate. The two faces of the panel 602 and 603 respectivelyconstitute a top face and a bottom face. The section shows two assemblybodies 100 and 200 as described above so only the main referencesthereon are repeated in order to avoid overcrowding the figure.

When parts are to be assembled, the two assembly bodies 100 and 200 arepresented on either side of the panel 600 and their central lockingportions 101 and 102 are inserted into the hole 601 in the panel,thereby enabling temporary locking to be obtained by axiallysnap-fastening these two bodies together. In this temporarily-lockedposition, the edges 103 and 203 of the assembly bodies 100 and 200 makecontact respectively with the bottom and top faces 603 and 602 of thepanel 600 to be supported (to within manufacturing tolerances). A hollowsection bar 10 is then disposed on each of the assembly bodies, afterwhich the two bars are rotated relative to each other, thereby givingrise to relative rotation of the two assembly bodies and thus engagingthe sloping ramp bayonet couplings between the two central lockingportions 101 and 201. As explained above, by virtue of the edges 103 and203 coming into abutment against the panel 600, the traction exerted onthe central portions 101 and 201 gives rise to radial outwardsdeformation of each of the assembly bodies, thereby automaticallylocking each of these bodies in the associated hollow section bar. Theprocess is extremely simple since it suffices merely to rotate one ofthe two bars through a quarter turn and no external tool is needed. Whenan assembly made in this way is to be disassembled, it suffices merelyto rotate the two bars 10 in question in the opposite direction, andthen disengage the assembly bodies which become accessible after thehollow bars have been removed.

FIG. 5 shows the vertical organization of various component parts of apiece of furniture having casters and two horizontal slabs, and makinguse of several assembly devices of the invention. This organization alsoserves to illustrate a possible variant of the invention in which anassembly body referenced 300 is in the form of a cylindrical plug whosemain portion 301 constitutes the central locking portion terminated by amale or female sloping ramp bayonet coupling 307 (not visible in FIG.5), with the remainder thereof being essentially undeformable andconstituting both an abutment and a mask hiding the bayonet coupling.The top portion of the plug-forming assembly body has means forpreventing it from rotating, e.g. a slot 321. It is generally preferablefor such an assembly body in the form of a cylindrical plug to beprovided with sloping ramp bayonet coupling of the female type. Theassembly process is entirely similar to that described with reference toFIG. 4. For the top slab 800 having a hole 801 and faces 802 and 803, itsuffices to bring together a plug 300 and an assembly body 200 havingcorresponding sloping ramp bayonet couplings. After the assembly bodieshave been temporarily locked together by axial snap-fastening, a hollowbar 10 is put into place on the locking body 200 and then said assemblybody 200 is rotated relative to the plug 300 in order to obtainautomatic locking between the hollow bar and the assembly body insertedtherein by rotation through a quarter turn only. The procedure for thebottom slab 700 having a hole 701 and faces 702 and 703 is exactly thesame as that described with reference to FIG. 4, where two assemblybodies 100 and 200 having inclined slope bayonet couplings are used.After the two assembly bodies 100 and 200 have been snap-fastened toeach other by axial displacement, the corresponding hollow bars 10 areput into place and the two bars are caused to rotate relative to eachother through a quarter turn in order to obtain secure locking on eitherside of the slab 700. At the bottom end, there are units which areconventional in this field, serving to receive wheels: these unitscomprise a bottom plug 510 and caster means 530 having wheels 540 and ahousing 550, said housing having a rod 560 extending upwards with agroove 750 for connection to the plug 510 by means of an inwardlyprojecting rim snapping therein (not shown).

Naturally numerous variants are possible, in particular for fixing to avery wide range of hollow section bars. The section of FIG. 6 thus showsa hollow bar 20 of a different type having external T-slots 21, 22, 23,and 24 and internal angular spaces 25. Such bars are advantageous sincetheir external slots can be used for receiving supporting catches or forreceiving the rabbet of a wall, or indeed for receiving a decorativestrip. The use of such hollow bars presents no difficulty in the contextof the present invention. Although assembly bodies as described withreference to FIG. 1 could be used, it is preferable to provide assemblybodies having the same cross-section as the hollow bar, therebyspreading the clamping forces better while avoiding compressing thebottoms of the grooves. Thus, FIG. 6 shows an assembly body 400 whoseperipheral portion has a complementary cross-section with angularprojections 425 corresponding to the angular voids 25 in the hollow bar20. As before, it is advantageous to provide slits 406 organized ondiagonal planes parallel to a common direction corresponding to thecentral axis of the associated hollow bar 20.

More generally, and regardless of the substance used for making thebars, the invention makes it possible to solve assembly problems using avery wide variety of hollow bars, which bars are preferably polygonal incross-section. It is nevertheless advantageous to select assembly bodieswhich have cross-sections that are as complementary as possible to theinside sections of the hollow bars so as to spread out clamping forcesuniformly, thereby avoiding compressing the bottoms of the grooves whenthe bars are provided with grooves (as shown in FIG. 6). When usinghollow bars of round external section, it is advisable to provide facetstherein defining a polygonal profile inside the bar (which can be doneby placing an insert in each bar end).

The invention thus makes it possible to provide an assembly device whichis simple in design and reasonable in production cost. The assemblydevice makes assembly quick and easy, and in particular no tools arerequired for assembling or dismounting the corresponding pieces offurniture. At worst, it will be necessary to provide locking means foruse in the special case of an assembly body in the form of a plug (asshown in FIG. 5). It is important to observe that the device of theinvention makes it possible to ensure that hollow bars are keptaccurately in alignment, both longitudinally which is essential forcarrying vertical forces, and with respect to angular positioning whichmay be of great importance for the final appearance of the assembledpieces of furniture. In addition, with respect to appearance, it shouldbe observed that the assembly device is completely invisible onceassembly is completed.

FIGS. 7A and 7B show two pieces of furniture that can easily beassembled using the device of the invention, with said device being usedon all of the horizontal slabs. Thus, in FIG. 7A, there can be seen adesk-type piece of furniture 900 having walls P, and slabs T1, T2, T3,T4, and T5. The vertical framework of such a desk is easily providedusing assembly devices of the invention, with such assemblies buildingup the required vertical risers. Thus, by way of example, for the slabT2 forming a writing surface, bars 911 and 912 constitutes a supportingriser, with bar 910 finishing off the complex vertical riser. On theother side of the desk 900, a vertical riser is built up from bars 924,923, 922, 921, and 920 thus constituting a single column havingexcellent load-carrying properties. The height of a piece of furnitureis thus built up using such risers without reducing riser stiffness. Inaddition, this design makes it possible to provide prior packaging whichis much less bulky than would be the case for similar pieces offurniture assembled using the above-mentioned conventional systems. Forsuch a desk which may be 1650 mm high, the longest dimension of thepackage will be determined by the length of the top slab T5 which isgenerally 1250 mm, whereas using prior techniques there was no way ofmaking a package shorter than 1650 mm. The presence of plugs 300 on thetop slab T5 should also be observed.

FIG. 7B shows a different piece of furniture constituting a set ofshelves 950 built up from slabs T, walls P, and backpieces F. As before,each of the vertical risers is built up by assembling successive lengthsof hollow bar 955, 954, 953, 952, and 951. Here again, there are plugs300 on the top slab. As before, for a set of shelves 1700 mm high,having individual shelves which are 800 mm wide and 300 mm deep, thelongest dimension of the package is only 800 mm, whereas priortechniques cannot reduce package size below a length of 1700 mm.

Naturally, the invention is not limited in any way to the embodimentsdescribed above, but on the contrary covers any variant which usesequivalent means to reproduce the essential characteristics specified inthe claims.

Thus, for example, conical interfitting systems could be used forobtaining the radial expansion of at least one of the assembly bodies,or systems could be used having metal inserts glued to a structuremolded in plastic material or elastomer material in order to obtain thedesired radial deformation.

In other applications, e.g. when making structures for stands, theinvention also makes it possible to assemble bars to same-sectionmultiple connectors, in which case the spacer of the assembly device isreduced to a mere thrust washer disposed between each bar and/ormultiple connection branch.

We claim:
 1. An assembly device for assembling dismountable or modularfurniture elements, said elements being of the type comprising aframework and at least one rigid spacer held by said framework anddisposed substantially transversely relative thereto, the said assemblydevice comprising:a first assembly body (100) insertable in a hollow bar(10) constituting a portion of the framework, said first assembly bodycomprising a central locking portion (101) a first end of which iscapable of penetrating through an associated hole of the spacer, saidcentral locking portion further including first coupling means (107) atsaid first end, and a deformable peripheral portion (102) connected tosaid central locking portion via a central face (105) which projectsfrom a second end of said central locking portion opposite said firstend of said central locking portion, said peripheral portion having afree edge (103) capable of bearing against a first face of said spacerin a zone surrounding the hole provided therethrough, and a secondassembly body (200) having a free edge (203) capable of bearing againsta second face of the spacer opposite said first face, and said secondassembly body further having a central locking portion (201) associatedto said central locking portion (101) of said first assembly body (100)and likewise having a first end which is capable of penetrating intosaid hole, said central locking portion (201) of said second assemblybody further including second coupling means (207) at said first endthereof, said first and second coupling means constituting a slopingramp bayonet coupling (107, 207); andwherein said peripheral portion(102) of said first assembly body (100) is radially outwardly deformableunder the combined effect of a bearing of the free edge (103) thereofagainst said first face of said spacer and of a traction exerted on saidcentral locking portion (101) of said first assembly body, such that arelative rotation of the two assembly bodies (100, 200) in order tocouple them together through said sloping ramp bayonet coupling (107,207) exerts said traction of said central locking portion (101) of saidfirst assembly body, and consequently produces said radial outwarddeformation of said peripheral portion (102) of said first assemblybody, so that said relative rotation automatically locks said firstassembly body (100) in the associated hollow bar (10), and furthermorelocks said spacer between said free edge (103) of said first assemblybody and said free edge (203) of said second assembly body.
 2. Anassembly device according to claim 1, wherein the central lockingportion (101) of the first assembly body is cylindrical to define acentral axis thereof, and wherein the peripheral portion (102) of thefirst assembly body (100) includes planar facets (104) which aresubstantially parallel to the central axis of the central lockingportion, the planar facets projecting from the central face of the firstassembly body and corresponding to at least some inside faces of theassociated hollow bar.
 3. An assembly device according to claim 2,characterized by the fact that the first assembly body (100) has slits(106) facilitating radial deformation thereof under the effect oftraction exerted on the central locking portion (101) of said body, theslits (106) being provided in corner edges of the peripheral portion(102) of the assembly body, and extending into the common central face(105) of said body.
 4. An assembly device according claim 3,characterized in that the slits (106) are organized in diagonal planesthat intersect the central axis of the central locking portion (101) ofthe first assembly body.
 5. An assembly device according to claim 1,characterized by the fact that the central locking portions (101, 102)of the first and second assembly bodies (100, 200) are bothsubstantially in the form of a cylindrical chimney defining atrespective first ends thereof a male and a female sloping ramp bayonetcoupling (207, 107).
 6. An assembly device according to claim 5,characterized by the fact that the male coupling (207) includes aprojecting transverse head (252), said transverse head including atleast one sloping bottom facette (253) capable of co-operating with asloping ramp (108) provided on the corresponding central locking portion(101).
 7. An assembly device according to claim 5, characterized by thefact that the female coupling (107) includes at least one inclined ramp(108) disposed inside the chimney, said ramp being suitable forco-operating with the projecting transverse head (252) provided on thecorresponding central locking portion (201).
 8. An assembly deviceaccording to claim 7, characterized by the fact that the sloping ramp(108) is delimited by two snap-fastening ridges (111, 112).
 9. Anassembly device according to claim 7, characterized by the fact that thesloping ramp (108) is essentially plane and extends perpendicularly toan inlet facette (109) delimiting an orifice (110) provided to recievethe projecting transverse head (252) of the corresponding centralportion (201).
 10. An assembly device according to claim 7,characterized by the fact that the female coupling (107) includes twosloping ramps (108) symmetrically disposed about the axis of the chimney(101).
 11. An assembly device according to claim 5, characterized by thefact that the sloping ramp bayonet coupling takes effect after the twoassembly bodies (100, 200) have rotated through approximately onequarter of a turn relative to each other.
 12. An assembly deviceaccording to claim 5, characterized by the fact that the male and femalesloping ramp bayonet couplings (207, 107) further include quicksnap-fastening means (255, 113) enabling them to be temporarily lockedtogether by axial displacement of the two assembly bodies (100, 200)prior to said bodies being rotated relative to each other.
 13. Anassembly device according to claim 12, characterized by the fact thatthe quick snap-fastening means is constituted by a stud and dimplesystem, preferably having two studs (255) on the projecting transversehead (252) of the male coupling (207), and two dimples (113) on theinside wall of the chimney (101) carrying the female coupling (107). 14.An assembly device according to claim 1, characterized by the fact thatthe first and second assembly bodies (100, 200) are generally identicalin structure, and differ from each other essentially only by the slopingramp bayonet coupling (107, 207).
 15. An assembly device according toclaim 14, characterized by the fact that the two assembly bodies (100,200) include respective peripheral portions (102, 202) such thatidentical hollow bars (10) can be used on either side of the spacer inquestion.
 16. An assembly device according to claim 15, characterized bythe fact that the peripheral portions (102, 202) of the assembly bodies(100, 200) are substantially square or rectangular in cross-section. 17.An assembly device according to claim 15, associated with a hollow bar(20) having angular internal voids (25), the assembly device beingcharacterized by the fact that the peripheral portions of the assemblybodies (400) are complementary in cross-section, having correspondingangular projections (425).
 18. An assembly device according to claim 1,characterized by the fact that the second assembly body (300) is in theform of a cylindrical plug whose main portion constitutes the centrallocking portion (301) terminated with male or female sloping rampbayonet couplings (307), and whose remaining portion (320) isessentially undeformable and constitutes both an abutment surface and amask for hiding the bayonet coupling.
 19. An assembly device accordingto claim 1, characterized by the fact that each of the assembly bodies(100, 200, 300, 400) is constituted by a single piece of plasticmaterial, preferably obtained by injection molding.
 20. An assemblydevice for assembling a hollow-section bar and a spacer member, theassembly device comprising:first and second assembly bodies having freeedges of peripheral portions respectively for bearing against oppositefaces of a spacer member and central locking portions having first endsfor entering a hole through the spacer member when the free edges of theperipheral portions bear against the opposite faces of the spacermember, the peripheral portion of the first assembly body comprisingdeformable facet members for disposition in correspondence with at leastportions of inner faces of a hollow section of a bar, whereby to rotatethe first assembly body with the bar when the facet members are disposedin the hollow section of the bar and the bar is rotated, edges of thefacet members being connected together into the free edge of theperipheral portion of the first assembly body; a common central facemember connected to a portion of each of the facet members that isspaced from the free edge of the peripheral portion of the firstassembly body toward a second end of the central locking portion of thefirst assembly body that is opposite the first end thereof; and couplingmeans on the first ends of the central locking portions of the first andsecond assembly bodies, the coupling means comprising a bayonet and asloping ramp for progressively coupling the central portions togetherwhen the first and second assembly bodies are relatively rotated,whereby rotation of the first assembly body with the bar when the freeedges of the peripheral portions of the first and second assembly bodiesbear against the spacer member and the central locking portions of thefirst and second assembly bodies are in the hole through the spacermember progressively tractions the central locking member and connectedcommon central face member of the first assembly body in the directionfrom the second to the first end of the central locking member and,thereby, deforms the facet members radially outwards into firmengagement with the inner faces of the hollow section of the bar.